Bit



June 8 1926,

P.' BASMAISON BIT Filed Deo'. 15. w23

Patented .lune 8, 1926.

llldlll STATES PIERRE BASMAISON, OF SAN FRANCISCO, CALIFORNIA..

BIT.

Application led December 15, 1923. Serial No. 680,892.

My invention relates to bits for woodworking tools and machines, such as bench planes, spolre shares, chisels7 jointers, surtacers and the like; and one of the objects of the invention is to provide a bit having a replaceable cutter such that periect setting and alignment ot' the cutter in the bit follows the assembling of the parts as a matter of mechanical certainty instead ot as a matter' or skillful handling.

Another object is to provide a bit a'lapted to employ a thin cutter that may be replaced when dull as readily' as blades are replaced in a safety razor.

Another object is to provide a bit having a replaceable cutter formed with. a double bevel cutting edge, and having its cutter end so shaped that the lateral ifaces ofthe bit adjacent the cutter lie in planes coincident with the bevels thereof7 thus insuring correct sharpening` of the cutter while positioned in the bit, if desired.

My invention possesses other objects and features or" advantage, some of which, with the foregoing, will be set 'forth in the tollowing description of the preferred torni ot my invention which is illustrated in the drawings accoinpanying and forming part ot the specification. lt is to be understood that I do not limit myself to the showing made by the said drawings and description, as I may adopt variations oit the preferred form within the scope ot my invention as set forth in the claims.

Referring to the drawings v Figure 1 is a central vertical section thru one o't' my bits assembled in a .low angle block plane.

Figure 2 is a side elevation ot my bit.

Figure 3 is a plan view ot the under side of the bit.

Figure l is a side view of a chisel showing a modified embodiment ot my invention.

Figure 5 is an end view ot a jointer head r showing another adaption ot' my invention.

Figure 6 is a side view of the spring employed in the adaption of my invention illustrated in Figure The bit olf my invention comprises a cutter blade 2 formed with the usual slot 3 extending longitudinally ther'ethru along a median line and also provided with the usual transverse notches Ll on its bottom lateral iace adjacent on'e end. The opposite upper lateral lace of the cutter blade is formed with a rabbet G having a shoulder 7, to provide a recess for the reception of a cutter 8 having a. rear non-cutting edge 9 complementary to the shoulder 7 of the rabbet. The rabbet is formed in the beveled end of the blade which forms an angle of approximately 121/2o to the bottom lateral face, and the cutting edge of the cutter 8 is lormed by the intersection of the planes of the bevels 11, the plane ot each bevel forming an angle of approximately 121/2o with the median longitudinal plane of the cutter.

Overlying the cutter blade and secured thereto at the end opposite the cutter by rivets 12, is a clamp plate 13 adapted to be pressed into clamping Contact with the cutter 8, and provided with a slot 14e in register with the slot 3 of the cutter blade. The end 16 of the Clamp plate adjacent the cutter is curved downwardly to form a clamping edge 17 and the upper tace ot the plate 13 contiguous to the clamping edge is beveled7 so that when the clamp plate is depressed the face of the bevel and the upper bevel 11 of the cutter lie in the same plane. In order to prevent chips from passing between the cutter and the bit I prefer to 'torni a second short but steep bevel immediately adjacent the clamping edge 17 o'l' the clamp plate 13 which forces the chips up and away from the point of contact ot the clamp plate and the cutter, and the sharp edge et the cutter blade 2 is also similarly relieved to avoid a weak thin edge under the cutter.

Means are provided :tor resiliently retaining the cutter in position in the cutter blade when not secured by the clamp plate. This is accomplished by a plate spring 18 suitably secured to the upper lateral face of the cutter blade and so arranged that the tree end ot the spring engages the cutter with sufficient torce to retain it in place, but not su'liicient to prevent its ready removal. The free end ot the spring overlies the cutter at the point of contact of the edge 1T of the clamp plate 13 so that when the plate is depressed the spring is held flat.

The bit disclosed in Figures 2 and 3 is adapted for use in a low angle block plane of a well-known make as illustrated in Figure 1, hence it is unnecessary to describe the mechanism of the plane in detail.

The bit is positioned in the plane bottom in the usual manner by the lever cap screw 19 passing thru the slots in the clamp lever and the cutter blade, and the clamp plate is depressed to clamp the cutter by the lever cap 20.

It is understood of course that the cutter is resiliently retained by the spring 18, in the cutter blade during the assembling of the cutter blade in the plane.

Longitudinal adjustmentvof the bit in the plane is effected in the usual manner by the frog 21, which engages the notches 4 in the cutter blade.

It will be noted that since the bottom bevel ll. of the cutter and the bottom lateral face of the cutter blade 2 lie in co-incident longitudinal planes, the. bit may be positioned in the plane in the same manner as the old style bit. If desired the cutter may be whetted by removing the bit as a unit from the plane and kholding the clamp plate in depressed position with thehand or a bolt during the operation. The bevels of the clamp plate tand cutter blade will insure correct positioning of the bit on the. stone.

In the modification of my invention disclosed in Figure 4 the bit is in the form of a chisel, comprising a body portion 25 which is tapered at one end and rabbeted to receive the cutter 26. A resilientclamp plate 27 is, suitably secured to the body portion and its tapered free end 28. is held in clamping engagement with the cutter 26 by count-ersunk screws 29 which are threadedy into the body portion adjacent the cutter. The cutter is formed with double bevels 31 and angularly disposed in the rabbet formed in the body portion so that its bottom bevel lies in a plane co-incident with the bottom face of the chisel. The tapered end 28 of the clamp plate 27 similarly lies in a plane co-ineident with the top bevel ofthe cutter.

Figure 5 illustrates the adapt-ion of my invention to a safety jzointer head wherein the bit comprises a cutter blade 33 having a tapered end 34 provided with a rabbet 36.

The cutter 3T disposed in the rabbet is in this instance formed with a single bevel cutting edge 3S lying in a plane co-incident with the tapered end of the cutter blade 33.

The clamp plate 39 comprises a throatv piece which is held in tight engagement with the. cutter 37 and secured in the head by a plurality of key plugs 41 wedged in tapered sockets 42 by the hollow7 set screws 43,. the throat piece 33 adjacent .the cutter blade insures clamping Contact of its forward end 45 with the cutter and provides a passage between the throat piece and the cutter blade for the reception of a corrugated plate spring 46 adapted to separate these last named elements when the key plugs are loosened thus facilitating the removal of the cutter'.

I claim l. A bit comprising a cutter blade having a rabbeted edge, a. loose replaceable cuttel adapted to seat in said rabbet and comprising a thin narrow flat smooth stri-p, and a clamp plate adapted to bear against said cutter blade and cutter to rigidly secure the Acutter' in the cutter blade.

2. A bit comprising al cutter blade having a rabbet formed in the end thereof, a detached cutter arranged in said rabbet, re-' silient means for retaining' said cutter in the rabbet, and a clamp plate adapted to rigidly secure the cut-ter in the rabbet.

my hand.

PIERRE BASMAISON.

A channel 44 formed in the face of 

